1. Field of the Invention
The present invention relates to an intake valve for an internal combustion engine. More specifically, the invention relates to a coaxial or two piece poppet valve that includes an inner and an outer valve for increasing the efficiency and performance of the engine.
2. Discussion of the Related Art
Internal combustion engines are well known in the art and used in a variety of different applications. A typical internal combustion engine employs valves to control the flow of atmosphere to and from the combustion chamber. The majority of known prior art valves are a single piece, having one spring retainer and various spring control arrangements to connect the valve to the rocker arm of an engine.
It has long been recognized that the efficiency of this valve arrangement is a major factor in the performance of the entire engine. As a result, several attempts have been made to maximize the potential flow dimensions of these valves. Since a homogenous air fuel mixture is also an important factor in the performance of internal combustion engines, many attempts to use the one-piece valve arrangement have sought to create a swirl affect in addition to increasing the over flow of the valve.
Increasing the flow dimension allowed by the intake valve automatically increases the power of the engine. Similarly, creating a more homogenous air fuel mixture also increases the power of the engine by breaking down the fuel into smaller particles that can be more easily combusted. The resulting effect of an increase in flow dimension or the homogeneity of the mixture, additionally increases fuel efficiency and reduces the environmentally damaging emissions of internal combustion engine. In a time of ever rising oil and gasoline costs, there is a real premium on fuel efficiency for engines. The value of reducing the harmful effects of pollution on the environment has also long been recognized.
The timing and control of the valve arrangement is also a major factor in the performance of the entire engine. As a result, numerous attempts to maximize valve timing over a broad range of constantly variable conditions such as load, speed, and atmosphere have also been explored. Additionally, the size of the valve is a major factor in the performance of the engine. The sizing of the valve is critical, and depends on the bore stroke ratio plus the combustion chamber shape. In many cases, combustion chamber shape dictates that the valve be shrouded on part of its open area creating an impediment to maximum atmospheric flow. The height of the valve lift is also critical in this aspect. Both increasing the lift of the valve and the unshielded area of the valve can allow more fuel inlet volume. This results in improved performance. In addition to these features, the weight of the valve as well as the weight of the springs that hold the valve in place have to resist the inertia forces on the valve such as a revolutions per minute (R.P.M.) increase. As the inertia forces go up, the valve springs require much more strength.
Other attempts have been made to create a valve with superior flow characteristics, or adding additional area into the valve. These prior art mechanisms are often complicated resulting in costly manufacturing and performance problems. For example, U.S. Pat. Nos. 6,237,549 and 5,357,914 to Huff the disclosures of which are hereby expressly incorporated by reference, illustrate attempts to provide a more efficient valve assembly by providing a vented valve. Huff's valve, however, exhibits numerous deficiencies. For example, Huff's valve includes a spring-loaded inner valve that may or may not close or seal. Huff's valve allows the inner valve to float with the spring behind it, therefore inertia forces, bounce, etc. can all effect the timing. Huff's patents specifically note that the inertia forces and the intake gas pressure differentials cause this inner valve to open and close. Therefore, there is no specific timing.
In contrast, the particular invention herein disclosed uses a main valve with an additional auxiliary valve that is easily manufactured and will fit in standard engines without additional modifications. In some embodiments, the springs in this particular assembly may or may not be used depending on the application of the particular unit. The springs are used to further isolate the outer valve from the inner valve and restrain it from erratic motions, soften the closure, etc. Preferably, there are only two spring seats and the seats are concentric on the outer valve. These seats are standard in configuration with no unusual or complicated areas.
The disclosed valve arrangement also allows the valves to rotate and keep the seats in good working condition for a much longer service life. There is no hindrance to any motion due to the additional valve outer valve. The control of the outer valve, as far as the ratio of the inner opening to the outer opening, is controlled by the fuel flow through the engine. In prior art valves, the larger the valve the more difficult it is for fuel to make that 90 degree turn at the valve and then exit through the small opening. The disclosed central opening relieves the pressure congestion at the middle of the intake port allowing the flow between the two openings to be dictated by the shielding of the outer valve and the size of the inner opening. Both openings are automatically adjusted, while open, not by any mechanical means, but by the pressure differential and the two springs of the assembly. When the valve is closed and sealed, the sealing is specifically tight and there is no ambiguity on the sealing surfaces as is in Huff's. Using the disclosed coaxial valve, the outer valve moves only to adjust the opening between the outer diameter and the inner diameter valve openings. This maximizes the flow through the valve reducing the shielded area on the large valve and also opening the center valve to reduce the pressure of the hard right angle turn on the normal large size intake valve.
As may be seen from the foregoing analysis, there have been some attempts to provide an intake valve that allows for increased power and fuel efficiency. These valves have not addressed several of the deficiencies in the art. Most of these prior art devices include complex mechanisms, cannot be easily retrofitted, and require considerable effort to install. Many of the devices are not robust enough to meet the demands of most high-powered engines.
What is therefore needed in light of the above is a valve assembly that exhibits enhanced robustness, increased power and efficiency. There is a further need for a valve assembly that can be easily used with existing internal combustion engines.